From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id E8ACF3858D37; Mon, 20 Feb 2023 08:16:23 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E8ACF3858D37 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1676880983; bh=mAh26Q3cn0lPvWVHW+nJVOpXzvPR+uvi78tOmWX4hlU=; h=From:To:Subject:Date:In-Reply-To:References:From; b=P9ykACFyOr+aHjrMb5w12hWUDgLeOSJmtsASdBRhhhzWXrBA/znePwT5MIFPHHsDw vMMTc067gIlpR7zMlh2RZJF+8jpsPU5DI4rCrJls+6eZDINEJjR1FFs7MXB8x7LAYJ wE4dT0UBv2JMn14wOtz0t5tDrKoXHVyuUx5AV0mA= From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/108839] Option for rerolling loops Date: Mon, 20 Feb 2023 08:16:20 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 13.0 X-Bugzilla-Keywords: missed-optimization X-Bugzilla-Severity: enhancement X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: everconfirmed bug_status blocked cf_reconfirmed_on Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108839 Richard Biener changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Blocks| |53947 Last reconfirmed| |2023-02-20 --- Comment #2 from Richard Biener --- Note the SLP loop vectorizer could be used to re-roll loops (for -Os?) by vectorizing with one element vectors and a "fractional" VF. I just never g= ot around playing with this idea (even when actually vectorizing but facing highly manually unrolled code vectorizing with a single vector and a "fractional" VF might be worth it for example for register pressure reasons= ). Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D53947 [Bug 53947] [meta-bug] vectorizer missed-optimizations=